Merge branch 'akpm' (incoming from Andrew)
[linux-3.10.git] / mm / fadvise.c
1 /*
2  * mm/fadvise.c
3  *
4  * Copyright (C) 2002, Linus Torvalds
5  *
6  * 11Jan2003    Andrew Morton
7  *              Initial version.
8  */
9
10 #include <linux/kernel.h>
11 #include <linux/file.h>
12 #include <linux/fs.h>
13 #include <linux/mm.h>
14 #include <linux/pagemap.h>
15 #include <linux/backing-dev.h>
16 #include <linux/pagevec.h>
17 #include <linux/fadvise.h>
18 #include <linux/writeback.h>
19 #include <linux/syscalls.h>
20 #include <linux/swap.h>
21
22 #include <asm/unistd.h>
23
24 /*
25  * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
26  * deactivate the pages and clear PG_Referenced.
27  */
28 SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice)
29 {
30         struct fd f = fdget(fd);
31         struct address_space *mapping;
32         struct backing_dev_info *bdi;
33         loff_t endbyte;                 /* inclusive */
34         pgoff_t start_index;
35         pgoff_t end_index;
36         unsigned long nrpages;
37         int ret = 0;
38
39         if (!f.file)
40                 return -EBADF;
41
42         if (S_ISFIFO(file_inode(f.file)->i_mode)) {
43                 ret = -ESPIPE;
44                 goto out;
45         }
46
47         mapping = f.file->f_mapping;
48         if (!mapping || len < 0) {
49                 ret = -EINVAL;
50                 goto out;
51         }
52
53         if (mapping->a_ops->get_xip_mem) {
54                 switch (advice) {
55                 case POSIX_FADV_NORMAL:
56                 case POSIX_FADV_RANDOM:
57                 case POSIX_FADV_SEQUENTIAL:
58                 case POSIX_FADV_WILLNEED:
59                 case POSIX_FADV_NOREUSE:
60                 case POSIX_FADV_DONTNEED:
61                         /* no bad return value, but ignore advice */
62                         break;
63                 default:
64                         ret = -EINVAL;
65                 }
66                 goto out;
67         }
68
69         /* Careful about overflows. Len == 0 means "as much as possible" */
70         endbyte = offset + len;
71         if (!len || endbyte < len)
72                 endbyte = -1;
73         else
74                 endbyte--;              /* inclusive */
75
76         bdi = mapping->backing_dev_info;
77
78         switch (advice) {
79         case POSIX_FADV_NORMAL:
80                 f.file->f_ra.ra_pages = bdi->ra_pages;
81                 spin_lock(&f.file->f_lock);
82                 f.file->f_mode &= ~FMODE_RANDOM;
83                 spin_unlock(&f.file->f_lock);
84                 break;
85         case POSIX_FADV_RANDOM:
86                 spin_lock(&f.file->f_lock);
87                 f.file->f_mode |= FMODE_RANDOM;
88                 spin_unlock(&f.file->f_lock);
89                 break;
90         case POSIX_FADV_SEQUENTIAL:
91                 f.file->f_ra.ra_pages = bdi->ra_pages * 2;
92                 spin_lock(&f.file->f_lock);
93                 f.file->f_mode &= ~FMODE_RANDOM;
94                 spin_unlock(&f.file->f_lock);
95                 break;
96         case POSIX_FADV_WILLNEED:
97                 /* First and last PARTIAL page! */
98                 start_index = offset >> PAGE_CACHE_SHIFT;
99                 end_index = endbyte >> PAGE_CACHE_SHIFT;
100
101                 /* Careful about overflow on the "+1" */
102                 nrpages = end_index - start_index + 1;
103                 if (!nrpages)
104                         nrpages = ~0UL;
105
106                 /*
107                  * Ignore return value because fadvise() shall return
108                  * success even if filesystem can't retrieve a hint,
109                  */
110                 force_page_cache_readahead(mapping, f.file, start_index,
111                                            nrpages);
112                 break;
113         case POSIX_FADV_NOREUSE:
114                 break;
115         case POSIX_FADV_DONTNEED:
116                 if (!bdi_write_congested(mapping->backing_dev_info))
117                         __filemap_fdatawrite_range(mapping, offset, endbyte,
118                                                    WB_SYNC_NONE);
119
120                 /* First and last FULL page! */
121                 start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
122                 end_index = (endbyte >> PAGE_CACHE_SHIFT);
123
124                 if (end_index >= start_index) {
125                         unsigned long count = invalidate_mapping_pages(mapping,
126                                                 start_index, end_index);
127
128                         /*
129                          * If fewer pages were invalidated than expected then
130                          * it is possible that some of the pages were on
131                          * a per-cpu pagevec for a remote CPU. Drain all
132                          * pagevecs and try again.
133                          */
134                         if (count < (end_index - start_index + 1)) {
135                                 lru_add_drain_all();
136                                 invalidate_mapping_pages(mapping, start_index,
137                                                 end_index);
138                         }
139                 }
140                 break;
141         default:
142                 ret = -EINVAL;
143         }
144 out:
145         fdput(f);
146         return ret;
147 }
148 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
149 asmlinkage long SyS_fadvise64_64(long fd, loff_t offset, loff_t len, long advice)
150 {
151         return SYSC_fadvise64_64((int) fd, offset, len, (int) advice);
152 }
153 SYSCALL_ALIAS(sys_fadvise64_64, SyS_fadvise64_64);
154 #endif
155
156 #ifdef __ARCH_WANT_SYS_FADVISE64
157
158 SYSCALL_DEFINE(fadvise64)(int fd, loff_t offset, size_t len, int advice)
159 {
160         return sys_fadvise64_64(fd, offset, len, advice);
161 }
162 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
163 asmlinkage long SyS_fadvise64(long fd, loff_t offset, long len, long advice)
164 {
165         return SYSC_fadvise64((int) fd, offset, (size_t)len, (int)advice);
166 }
167 SYSCALL_ALIAS(sys_fadvise64, SyS_fadvise64);
168 #endif
169
170 #endif